Schematic representation of fluorescence

Fig. 4 Explanation of the fluorescence-quenching effect [2]. — (A) chromatograms of the same quantities of saccharin and dulcin observed under UV 254 light, (B) schematic representation of fluorescence quenching, (C) spectral reflectance curves of saccharin and dulcin.

Fig. 7.10 Schematic representation of fluorescent nanotubes prepared through the alternate deposition of PEI and PTCDA in AAO membrane templates. (Reproduced from [119] with permission of the American Chemical Society, Copyright 2006 American Chemical Society).

Fig. 12 Schematic representation of Fluorescence Resonance Energy Transfer (FRET). The excitation of the donor occurs at wavelength Xi. The good spectral overlap of donor emission and acceptor excitation allows the transfer of the excitation from donor to acceptor. The acceptor emits at the longer wavelength X2.

Fig. 14 (a) Molecular structures of receptors employed in the work, (b) Schematic representation of fluorescent ion-imprinted mesoporous silica. Reprinted with permission from [62]... 

Fig. 5 Schematic representation of the electronic transitions during luminescence phenomena [5]. — A absorbed energy, F fluorescence emission, P phosphorescence, S ground state. S excited singlet state, T forbidden triplet transition.

Fig. 27 Schematic representation of the relationship between absorption and fluorescence emission of the molecules — m and m are the terms involved in the vibrational quantum numbers [4],...

Fig. 14 Schematic representation of the electronic transitions of photochemically excited substances Sq = ground state, Sj = first excited singlet state, T = forbidden triplet transition, N = ground state of a newly formed compound, A = absorption, F = fluorescence, P = phosphorescence.

Fig. 20 Schematic representation of an eiectric spark discharge chamber for the activation of gases at normal atmospheric pressure for the production of fluorescence in substances separated by thin-layer chromatography [2],...

Fig. 3a, b. Schematic representation of (a) conventional fluorescent sensor and (b) fluorescent sensor with signal amplification. Open rhombi indicate coordination sites and black rhombi indicate metal ions. The curved arrows represent quenching processes. In the case of a den-drimer, the absorbed photon excites a single fluorophore component, which is quenched by the metal ion regardless of its position... 

Fig. 2 A schematic representation of an HTRF assay for a protein-protein interaction. One protein is tagged with a fluorescent molecule whose emission spectra overlaps with the excitation of another fluorescent molecule. When they are in close proximity (above) the energy is transferred. When they diffuse apart (below) or are inhibited from coming together by a small molecule no FRET occurs...

Fig. 2 Schematic representation of characteristic absorption (A) and fluorescence (F) spectra of H- and J-aggregates (marked as H and J, respectively) as compared to those of the monomer molecule (M). The dashed spectrum FH means that H-aggregates could be nonfluorescent...

Figure S.6. Schematic representation of So and Si energy profiles for DEWAR formation in TB9A and TB9ACN. 2 The excited state funnel F is very close to the ground stale surface and therefore leads to fluorescence quenching (identifiable with rate constant k). Most of the molecules return to the anthracene form via pathway a, while only a few proceed to the Dewar form (pathway b), because F is placed to the left of the ground state barrier. The steric effect of the tert-butyl substituent is indicated by the broken line. Without this prefolding" of the anthracence form. Dewar formation is not observed. The top part of the figure contains a schematic description of the butterfly-type folding process, while the bottom part contains examples of actual molecules.

A schematic representation of this category of techniques is depicted in Figure 11.9. The intensity of the excitation light is sinusoidally modulated so that the fluorescence response from the sensor material is forced to follow the same sinusoidal law, but lagging behind the excitation light by a phase shift q>, which is expressed as... 

Figure 2.4. Schematic representation of processes which lead to fluorescence depolarization in proteins rotation of the protein molecule as a whole with correlation time rotation of the fluorophore with correlation time d, and excitation energy transfer, represented by the wavy arrow.

Figure 6.4. Schematic representation of a fluorescent immunoassay for theophylline utilizing enzymatic hydrolysis of an intramolecularly quenched theophylline conjugate of flavin adenine dinucleotide. (Reprinted from Ref. 5, with permission from Academic Press.)...

Figure 11. Schematic representation of a laser heating experiment in the DAC. The IR laser beam is directed onto the absorbing sample immersed in a compression medium acting also as thermal insulator. The thermal emission of the sample is employed for the temperature measurement, while the local pressure is obtained by the ruby fluorescence technique (see next section).

Fig. 2. Parameters affecting the efficiency of energy transfer. (A) Overlay of FITC emission spectrum and PE absorbance spectrum normalized to maximum fluorescence intensity and maximum optical density, respectively. FITC fluorescence intensity was measured as a function of emissions wavelength using a fluorimeter with an excitation wavelength of 488 nm. PE optical density was measured as a function of wavelength using a spectrophotometer. (B) Schematic representation of energy absorption and the possible pathways for the subsequent energy release (abbreviations as in the text).

Figure 21 Schematic representation of several head moieties (a) fluorescent chemo-sensor [36] (h) Ceo-based heads [34] (c) ligands containing suitable binding sites in a correct arrangement for metal ion complexation [35] (d) head moieties functionalized with reactive sites [37].

For our purpose, it is convenient to classify the measurements according to the format of the data produced. Sensors provide scalar valued quantities of the bulk fluid i. e. density p(t), refractive index n(t), viscosity dielectric constant e(t) and speed of sound Vj(t). Spectrometers provide vector valued quantities of the bulk fluid. Good examples include absorption spectra A t) associated with (1) far-, mid- and near-infrared FIR, MIR, NIR, (2) ultraviolet and visible UV-VIS, (3) nuclear magnetic resonance NMR, (4) electron paramagnetic resonance EPR, (5) vibrational circular dichroism VCD and (6) electronic circular dichroism ECD. Vector valued quantities are also obtained from fluorescence I t) and the Raman effect /(t). Some spectrometers produce matrix valued quantities M(t) of the bulk fluid. Here 2D-NMR spectra, 2D-EPR and 2D-flourescence spectra are noteworthy. A schematic representation of a very general experimental configuration is shown in Figure 4.1 where r is the recycle time for the system. 

FIGURE 1.6 Schematic representation of cell-based sensor (CBB) for pathogen detection. After binding to receptor on mammalian cells, pathogen or toxin will aid in the release of signaling molecules such as fluorescence or enzyme that can be detected using an appropriate sensor. 

Fig. 32 Schematic representation of the correlation of surface charge and growth of the aggregates for the various regions of the adsorption isotherm of SDS on alumina based on fluorescence data and zeta potential measurement...

Fig. 14. Schematic representation of energy levels and transitions for fluorescence and related processes kic, rate constant for interval conversion fcF, rate constant for fluorescence fcISC, rate constant for intersystems crossing fc[cp> rate constant for internal conversion from triplet state kp, rate constant for phosphorescence S, energy level for the first excited singlet state after solvent rearrangement for a polarity probe in a polar solvent.

Figure 1. Schematic representation of electron transfer sensitization. 1 photo-oxidation of sensitizer 2 forward electron transfer (fluorescence quenching) 3 back electron transfer 4 product formation...

Figure 1. A schematic representation of a typical fluorescent-decay process illustrating the migration of energy by resonance exchange from ion to ion and its subsequent...

Fig. 24. Schematic representation of the fluorescence yields in a level-crossing experiment, (a) A Lorentzian yield curve, (b) A dispersion yield curve.

We have seen earlier that Eu3+ possess two resonance levels, Do mid 5Z>i, from which fluorescence transitions to the J manifold of 1F takes place. The 5Do - 7Fo transition is strictly forbidden for regular octahedral symmetry but is observed in some complexes due to the lack of centro-symmetry. The intensity of the fluorescence transition is not directly dependent only on the amount of T 4f energy transfer, but mainly on the transition probabilities from a particular resonance level to the various J manifolds. However, the transition probabilities are sensitive functions depending on the ligand. A schematic representation of the... 

Fig. 9 Schematic representation of the scintillation proximity assay of (S)-propanolol using imprinted microspheres. The light green area represents the aromatic antenna element, (a) The bound, tritium-labeled (S)-propranolol triggers the scintillator to generate a fluorescent light, (b) When the tritium-labeled (S)-propranolol is displaced by the unlabeled (S)-propranolol, it is too far away from the scintillator antenna to transfer efficiently the radiation energy therefore, no fluorescence can be generated (as described in [62])...

Fig. 10 Schematic representation of the two approaches mainly used in EzILAs. (a) The enzyme conjugate and the analyte compete for the selective binding sites of the polymer finally, a substrate is converted into a product that generates a chemical signal (e.g., fluorescence, absorbance, electrochemical) at a rate which is proportional to the amount of bound enzyme and hence to the concentration of analyte in the sample, (b) Direct assay where the analyte is the enzyme which is quantified by a coupled enzymatic reaction...

Fig. 11 Schematic representation of the two approaches mainly used in FILAs. (1) The analyte or analog of it is labeled with a fluorophore and the polymer is imprinted with the native analyte. (2) The probe is a fluorescent species unrelated to the analyte structure and the polymer is imprinted with the native analyte. (3) The analyte or its analog is labeled with a fluorophore and the polymer is imprinted with it...

Fig. 21.2. (A) Schematic representation of the electrochemical DNA biosensing procedures based on Av-GEB. (B) Confocal laser scanning fluorescence microphotograph of Av-GEB transducers submitted to (i) non-biotinylated fluorescein (background adsorption) and (ii) 80 pmol of biotinylated fluorescein. Laser excitation was at 568 nm. Voltage 352 V (more details in Zacco et at., [65]).

Fig. 9 Schematic representation of the time-domain DLR (f-DLR) scheme. The shortlived indicator fluorescence and the long-lived phosphorescence of the inert reference beads are simultaneously excited and measured in two time gates. The first (Aex) is in the excitation period where the light source is on and the signal obtained is composed of short-lived fluorescence and long-lived luminescence. The second gate (Aem) is opened in the emission period where the intensity is exclusively composed of the reference luminescence [18]...

---